The present invention relates to a charger that includes two systems of protection circuits to inhibit charging a battery, at least when the battery is not connected to a connecting portion for charging, to thereby suppress output of a charging voltage from the connecting portion.
A charger of this type is conventionally known as disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2012-143062. In the charger, a pulse-width modulation (PWM) output setting unit to feed back a charging current to a charging device that conducts PWM control of a charging current to a battery and a power source unit to supply a power-supply voltage to the charging device for operation thereof are provided as two systems of protection circuits.
In the charger, when the battery is not connected to a connecting portion, output of the charging voltage from the charging device to the connecting portion is inhibited by setting an output from the PWM output setting unit to a value for setting the charging current to zero and setting an output voltage from the power source unit to 0V.
According to the charger of this type, therefore, even when a malfunction or failure occurs in one of the protection circuits, it is possible to inhibit output of a charging voltage from the charging device to the connecting portion by an operation of the other of the protection circuits, and thus to achieve an enhanced safety of the charger.